Montreal Protocol


The Montreal Protocol, or more precisely the Montreal Protocol on Substances that Deplete the Ozone Layer, is a multilateral environmental agreement that was adopted in 1987. It regulates the consumption and production of man-made chemicals called Ozone Depleting Substances which, as the name suggests, are extremely detrimental for the Earth’s stratospheric ozone layer. The ozone layer plays a crucial role in the protection of humans and the environment from solar ultraviolet radiation, which contributes, among others, to skin cancer and eye cataracts.

The Montreal Protocol is largely considered one of the most successful agreements in environmental history. It is currently ratified by all 197 UN member countries and its implementation has been extremely effective: 98% of ODS have been phased out and it is estimated that the ozone layer will recover approximately by 2050. The phase-out of ODS also contributes to the efforts against climate change, given that some of these chemicals (most importantly hydrochlorofluorocarbons or HCFCs) have a warming potential much greater than other commonly diffused greenhouse gases. 


According to Nasa, in 2019 the Ozone Hole was at its smallest since its discovery in 1982

Several factors contributed to the success of the agreement.

Firstly, a trade provision was included in which parties to the Protocol committed to trading in ODS only with other signatory countries; this constituted an incredibly powerful incentive for participation.

Secondly, the agreement was constructed in a way that allowed it to be adapted to advances in scientific knowledge: as a matter of fact, it was signed on the basis of the precautionary principle and strengthened over time. For example, once the damaging impact of HCFCs on the climate was fully recognised, the Montreal amendment (2007) was adopted to fasten their elimination and, under the Kigali Amendment (2016), countries committed to reducing the use of hydrofluorocarbons, which were initially used as an alternative for ODS but are now being phased out due to their severe impact on climate change.

Another strength of the Montreal Protocol is the framework it put in place to ensure the participation of developing countries, which could commit to a more gradual phase-out and received both financial and technical assistance through the Multilateral fund. This represents an important instance of the implementation of the principle of common but differentiated responsibilities.

The Montreal Protocol reminds us of the incredible potential of international cooperation and will hopefully act as an inspiration for the much needed commitment for climate action.